diff --git a/vendor.conf b/vendor.conf
index 45ae1fc971..a1833eff38 100755
--- a/vendor.conf
+++ b/vendor.conf
@@ -74,7 +74,7 @@ github.com/tonistiigi/units                         6950e57a87eaf136bbe44ef2ec8e
 github.com/xeipuuv/gojsonpointer                    02993c407bfbf5f6dae44c4f4b1cf6a39b5fc5bb
 github.com/xeipuuv/gojsonreference                  bd5ef7bd5415a7ac448318e64f11a24cd21e594b
 github.com/xeipuuv/gojsonschema                     f971f3cd73b2899de6923801c147f075263e0c50 # v1.1.0
-golang.org/x/crypto                                 bac4c82f69751a6dd76e702d54b3ceb88adab236
+golang.org/x/crypto                                 2aa609cf4a9d7d1126360de73b55b6002f9e052a
 golang.org/x/net                                    0de0cce0169b09b364e001f108dc0399ea8630b3
 golang.org/x/oauth2                                 ef147856a6ddbb60760db74283d2424e98c87bff
 golang.org/x/sync                                   cd5d95a43a6e21273425c7ae415d3df9ea832eeb
diff --git a/vendor/golang.org/x/crypto/chacha20/chacha_arm64.go b/vendor/golang.org/x/crypto/chacha20/chacha_arm64.go
index 87f1e369cc..b799e440b4 100644
--- a/vendor/golang.org/x/crypto/chacha20/chacha_arm64.go
+++ b/vendor/golang.org/x/crypto/chacha20/chacha_arm64.go
@@ -2,8 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build go1.11
-// +build !gccgo,!appengine
+// +build go1.11,!gccgo,!purego
 
 package chacha20
 
diff --git a/vendor/golang.org/x/crypto/chacha20/chacha_arm64.s b/vendor/golang.org/x/crypto/chacha20/chacha_arm64.s
index b3a16ef751..891481539a 100644
--- a/vendor/golang.org/x/crypto/chacha20/chacha_arm64.s
+++ b/vendor/golang.org/x/crypto/chacha20/chacha_arm64.s
@@ -2,8 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build go1.11
-// +build !gccgo,!appengine
+// +build go1.11,!gccgo,!purego
 
 #include "textflag.h"
 
diff --git a/vendor/golang.org/x/crypto/chacha20/chacha_generic.go b/vendor/golang.org/x/crypto/chacha20/chacha_generic.go
index 098ec9f6be..7c498e90d9 100644
--- a/vendor/golang.org/x/crypto/chacha20/chacha_generic.go
+++ b/vendor/golang.org/x/crypto/chacha20/chacha_generic.go
@@ -136,6 +136,33 @@ func quarterRound(a, b, c, d uint32) (uint32, uint32, uint32, uint32) {
 	return a, b, c, d
 }
 
+// SetCounter sets the Cipher counter. The next invocation of XORKeyStream will
+// behave as if (64 * counter) bytes had been encrypted so far.
+//
+// To prevent accidental counter reuse, SetCounter panics if counter is
+// less than the current value.
+func (s *Cipher) SetCounter(counter uint32) {
+	// Internally, s may buffer multiple blocks, which complicates this
+	// implementation slightly. When checking whether the counter has rolled
+	// back, we must use both s.counter and s.len to determine how many blocks
+	// we have already output.
+	outputCounter := s.counter - uint32(s.len)/blockSize
+	if counter < outputCounter {
+		panic("chacha20: SetCounter attempted to rollback counter")
+	}
+
+	// In the general case, we set the new counter value and reset s.len to 0,
+	// causing the next call to XORKeyStream to refill the buffer. However, if
+	// we're advancing within the existing buffer, we can save work by simply
+	// setting s.len.
+	if counter < s.counter {
+		s.len = int(s.counter-counter) * blockSize
+	} else {
+		s.counter = counter
+		s.len = 0
+	}
+}
+
 // XORKeyStream XORs each byte in the given slice with a byte from the
 // cipher's key stream. Dst and src must overlap entirely or not at all.
 //
diff --git a/vendor/golang.org/x/crypto/chacha20/chacha_noasm.go b/vendor/golang.org/x/crypto/chacha20/chacha_noasm.go
index ec609ed868..4635307b8f 100644
--- a/vendor/golang.org/x/crypto/chacha20/chacha_noasm.go
+++ b/vendor/golang.org/x/crypto/chacha20/chacha_noasm.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !arm64,!s390x,!ppc64le arm64,!go1.11 gccgo appengine
+// +build !arm64,!s390x,!ppc64le arm64,!go1.11 gccgo purego
 
 package chacha20
 
diff --git a/vendor/golang.org/x/crypto/chacha20/chacha_ppc64le.go b/vendor/golang.org/x/crypto/chacha20/chacha_ppc64le.go
index d0ec61f08d..b799330341 100644
--- a/vendor/golang.org/x/crypto/chacha20/chacha_ppc64le.go
+++ b/vendor/golang.org/x/crypto/chacha20/chacha_ppc64le.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !gccgo,!appengine
+// +build !gccgo,!purego
 
 package chacha20
 
diff --git a/vendor/golang.org/x/crypto/chacha20/chacha_ppc64le.s b/vendor/golang.org/x/crypto/chacha20/chacha_ppc64le.s
index 533014ea3e..23c6021643 100644
--- a/vendor/golang.org/x/crypto/chacha20/chacha_ppc64le.s
+++ b/vendor/golang.org/x/crypto/chacha20/chacha_ppc64le.s
@@ -19,7 +19,7 @@
 // The differences in this and the original implementation are
 // due to the calling conventions and initialization of constants.
 
-// +build !gccgo,!appengine
+// +build !gccgo,!purego
 
 #include "textflag.h"
 
diff --git a/vendor/golang.org/x/crypto/chacha20/chacha_s390x.go b/vendor/golang.org/x/crypto/chacha20/chacha_s390x.go
index cd55f45a33..a9244bdf4d 100644
--- a/vendor/golang.org/x/crypto/chacha20/chacha_s390x.go
+++ b/vendor/golang.org/x/crypto/chacha20/chacha_s390x.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !gccgo,!appengine
+// +build !gccgo,!purego
 
 package chacha20
 
diff --git a/vendor/golang.org/x/crypto/chacha20/chacha_s390x.s b/vendor/golang.org/x/crypto/chacha20/chacha_s390x.s
index de52a2ea8d..89c658c410 100644
--- a/vendor/golang.org/x/crypto/chacha20/chacha_s390x.s
+++ b/vendor/golang.org/x/crypto/chacha20/chacha_s390x.s
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !gccgo,!appengine
+// +build !gccgo,!purego
 
 #include "go_asm.h"
 #include "textflag.h"
diff --git a/vendor/golang.org/x/crypto/poly1305/mac_noasm.go b/vendor/golang.org/x/crypto/poly1305/mac_noasm.go
index a8dd589ae3..b0c2cd0561 100644
--- a/vendor/golang.org/x/crypto/poly1305/mac_noasm.go
+++ b/vendor/golang.org/x/crypto/poly1305/mac_noasm.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !amd64,!ppc64le gccgo appengine
+// +build !amd64,!ppc64le gccgo purego
 
 package poly1305
 
diff --git a/vendor/golang.org/x/crypto/poly1305/sum_amd64.go b/vendor/golang.org/x/crypto/poly1305/sum_amd64.go
index df56a652ff..35b9e38c90 100644
--- a/vendor/golang.org/x/crypto/poly1305/sum_amd64.go
+++ b/vendor/golang.org/x/crypto/poly1305/sum_amd64.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build amd64,!gccgo,!appengine
+// +build !gccgo,!purego
 
 package poly1305
 
diff --git a/vendor/golang.org/x/crypto/poly1305/sum_amd64.s b/vendor/golang.org/x/crypto/poly1305/sum_amd64.s
index 8c0cefbb3c..8d394a212e 100644
--- a/vendor/golang.org/x/crypto/poly1305/sum_amd64.s
+++ b/vendor/golang.org/x/crypto/poly1305/sum_amd64.s
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build amd64,!gccgo,!appengine
+// +build !gccgo,!purego
 
 #include "textflag.h"
 
diff --git a/vendor/golang.org/x/crypto/poly1305/sum_noasm.go b/vendor/golang.org/x/crypto/poly1305/sum_noasm.go
index 32a9cef6bb..2e3ae34c7d 100644
--- a/vendor/golang.org/x/crypto/poly1305/sum_noasm.go
+++ b/vendor/golang.org/x/crypto/poly1305/sum_noasm.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build s390x,!go1.11 !amd64,!s390x,!ppc64le gccgo appengine nacl
+// +build s390x,!go1.11 !amd64,!s390x,!ppc64le gccgo purego
 
 package poly1305
 
diff --git a/vendor/golang.org/x/crypto/poly1305/sum_ppc64le.go b/vendor/golang.org/x/crypto/poly1305/sum_ppc64le.go
index 3233616935..92597bb8c2 100644
--- a/vendor/golang.org/x/crypto/poly1305/sum_ppc64le.go
+++ b/vendor/golang.org/x/crypto/poly1305/sum_ppc64le.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build ppc64le,!gccgo,!appengine
+// +build !gccgo,!purego
 
 package poly1305
 
diff --git a/vendor/golang.org/x/crypto/poly1305/sum_ppc64le.s b/vendor/golang.org/x/crypto/poly1305/sum_ppc64le.s
index 4e20bf299a..4e02813879 100644
--- a/vendor/golang.org/x/crypto/poly1305/sum_ppc64le.s
+++ b/vendor/golang.org/x/crypto/poly1305/sum_ppc64le.s
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build ppc64le,!gccgo,!appengine
+// +build !gccgo,!purego
 
 #include "textflag.h"
 
diff --git a/vendor/golang.org/x/crypto/poly1305/sum_s390x.go b/vendor/golang.org/x/crypto/poly1305/sum_s390x.go
index a8920ee9d2..5f91ff84a9 100644
--- a/vendor/golang.org/x/crypto/poly1305/sum_s390x.go
+++ b/vendor/golang.org/x/crypto/poly1305/sum_s390x.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build s390x,go1.11,!gccgo,!appengine
+// +build go1.11,!gccgo,!purego
 
 package poly1305
 
diff --git a/vendor/golang.org/x/crypto/poly1305/sum_s390x.s b/vendor/golang.org/x/crypto/poly1305/sum_s390x.s
index ca5a309d86..806d1694b0 100644
--- a/vendor/golang.org/x/crypto/poly1305/sum_s390x.s
+++ b/vendor/golang.org/x/crypto/poly1305/sum_s390x.s
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build s390x,go1.11,!gccgo,!appengine
+// +build go1.11,!gccgo,!purego
 
 #include "textflag.h"
 
diff --git a/vendor/golang.org/x/crypto/poly1305/sum_vmsl_s390x.s b/vendor/golang.org/x/crypto/poly1305/sum_vmsl_s390x.s
index e60bbc1d7f..b439af9369 100644
--- a/vendor/golang.org/x/crypto/poly1305/sum_vmsl_s390x.s
+++ b/vendor/golang.org/x/crypto/poly1305/sum_vmsl_s390x.s
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build s390x,go1.11,!gccgo,!appengine
+// +build go1.11,!gccgo,!purego
 
 #include "textflag.h"